How deep is Long Lake?

Long Lake reaches a maximum depth of 84 feet in the Michigan DNR Inland Lake Contours survey. Most of it is far shallower: the survey charts 8 closed depth contours over about 283 acres, and half of that water sits inside the 30 ft line. The 84 ft figure is a single recorded sounding rather than a closed contour, so the deepest line you can actually trace on the map is 80 ft.

Where is the deepest part of Long Lake?

The deepest charted water on Long Lake lies inside the 80 ft contour, toward the northern end of the lake. That contour encloses 1.9 acres, under 1% of the mapped water, so it is a small target on a small water, the depth chart above gives the contour to line up on.

How much of Long Lake is shallower than 30 feet?

About half. The 30 ft contour encloses 132 acres of the roughly 283 acres inside the outer 10 ft line, so the other half of the water is shallower than 30 feet. The sharpest drop is between 10 and 20 feet, where the mapped water sheds 116 acres.

How accurate is this Long Lake depth map?

The contours come from the Michigan DNR Inland Lake Contours survey, retrieved August 2026 and last rebuilt on August 19, 2026. Depths change over time with water levels and sediment, so treat this map as a planning guide for fishing, and never use it for navigation. Acreages are computed from the published contour geometry, not from a separate area survey, so read them as close approximations.

Michigan lake depth maps

Long Lake depth map

Long Lake in Montmorency County, Michigan reaches a depth of 84 feet. Long Lake is charted here across 8 closed depth contours, from the 10 ft line down to 80 ft, enclosing about 283 acres of water. Half of that water lies inside the 30 ft line, and only 1.9 acres lie inside the deepest one. Every contour is on the interactive map below, free and without an account.

Data: Michigan DNR Inland Lake Contours (public record). Contours closed, checked and area-computed by Jordan Carter, founder of GilledIt · page updated August 19, 2026

Long Lake depth chart: 8 depth contours from 10 to 80 ft

Data: Michigan DNR Inland Lake Contours (public record), retrieved August 2026 · depths change over time · not for navigation

Long Lake depth chart data: water enclosed by each contour
Depth contour	Water inside it	Share of mapped water
10 ft	283 acres	100%
20 ft	167 acres	59%
30 ft	132 acres	47%
40 ft	77 acres	27%
50 ft	48 acres	17%
60 ft	31 acres	11%
70 ft	15 acres	5.4%
80 ft	1.9 acres	under 1%

Acreages are computed from the closed Michigan DNR Inland Lake Contours contour rings, with islands subtracted. Shares are of the 283 acres inside the outermost charted contour (the 10 ft line), which is the outer edge of the mapped water, several state files carry no 0 ft shoreline line, so this is not the same as a share of the lake's published surface area. The survey also records a 84 ft sounding, marked as a point rather than a closed contour, so it is not charted as a band.

Fishing Long Lake: a wide shallow flat over a deep hole

Inside its outermost 10 ft contour the survey charts about 283 acres of Long Lake, with the 30 ft line enclosing half of it, so the bulk of this Montmorency County water sits on a shallow flat, with the real depth packed into one part of the basin. The sharpest change on the chart is between 10 and 20 ft, where the mapped water loses 116 acres in 10 ft of depth, that band is the contour to work first, because it is where the bottom stops being flat. The deepest 80 ft contour holds 1.9 acres, under 1% of the mapped water, toward the northern end of the lake. 84 ft of water makes this a two-story fishery: warm-water fish hold the 10-to-30 ft ground while the basin can stay cold below the summer thermocline, and the traffic between the two runs along the 10–20 ft break at first and last light.

Ice fishing on Long Lake

Long Lake freezes later and less evenly than the shallow waters around it, and the winter bite sets up on the first real break rather than out over the 80 ft hole. The 10–20 ft band on the chart above is that edge: 116 acres of bottom tilt away there, and panfish and walleye slide up and down it through the day. Late ice pushes fish back onto the 10-to-30 ft flat. Check ice thickness locally before you walk out.

Long Lake depth map FAQs

How deep is Long Lake?: Long Lake reaches a maximum depth of 84 feet in the Michigan DNR Inland Lake Contours survey. Most of it is far shallower: the survey charts 8 closed depth contours over about 283 acres, and half of that water sits inside the 30 ft line. The 84 ft figure is a single recorded sounding rather than a closed contour, so the deepest line you can actually trace on the map is 80 ft.
Where is the deepest part of Long Lake?: The deepest charted water on Long Lake lies inside the 80 ft contour, toward the northern end of the lake. That contour encloses 1.9 acres, under 1% of the mapped water, so it is a small target on a small water, the depth chart above gives the contour to line up on.
How much of Long Lake is shallower than 30 feet?: About half. The 30 ft contour encloses 132 acres of the roughly 283 acres inside the outer 10 ft line, so the other half of the water is shallower than 30 feet. The sharpest drop is between 10 and 20 feet, where the mapped water sheds 116 acres.
How accurate is this Long Lake depth map?: The contours come from the Michigan DNR Inland Lake Contours survey, retrieved August 2026 and last rebuilt on August 19, 2026. Depths change over time with water levels and sediment, so treat this map as a planning guide for fishing, and never use it for navigation. Acreages are computed from the published contour geometry, not from a separate area survey, so read them as close approximations.

Depth maps for lakes near Long Lake

Rainy Lake depth map · 98+ ft max · 10 mi away
Clear Lake depth map · 90+ ft max · 10 mi away
Francis Lake depth map · 83 ft max · 13 mi away
Beaver Lake depth map · 70+ ft max · 15 mi away
Sage Lakes depth map · 36+ ft max · 18 mi away

Mapped fishing venues near Long Lake

Long Lake in the venue directory covers access and fishing details for this water.

Rainy Lake · 10 mi away
Clear Lake · 10 mi away
Francis Lake · 13 mi away

Fishing in Michigan needs a state license: Michigan fishing license guide · all Michigan venues